Webs, such as thermoplastic films, have a variety of uses including component materials of absorbent articles (such as topsheets and backsheets), packaging (such as flow wrap, shrink wrap, and polybags), trash bags, food wrap, dental floss, wipes, electronic components, and the like. For many of these uses of webs, it can be beneficial for the web to have a textured, three-dimensional surface which can provide the surface of the web with a desirable feel (e.g., soft, silky), visual impression, and/or audible impression, as well as one or more desirable properties such as improved fluid handling or strength.
One of approaches to endow a desirable feel to webs is forming microtextures such as protrusions and recessions in the webs via technologies such as a vacuum forming process, hydroforming process and embossing process. With a typical vacuum forming process, a precursor web is heated and placed over a forming structure. Then a vacuum of air forces the precursor web to conform to the texture of the forming structure. With a typical hydroforming process, a precursor web is placed over a forming structure and high pressure and high temperature water jets force the precursor web to conform to the texture of the forming structure.
Micro-textured webs can be further deformed to have three-dimensionally macro aperture fluid transportation structures. Macro-apertured webs are utilized in a wide variety of industrial and consumer products. For example, apertured webs are known for use in disposable absorbent articles such as disposable diapers and feminine hygiene articles such as sanitary napkins, and the like. Such articles typically have a fluid pervious topsheet, a fluid impervious breathable backsheet, and an absorbent core disposed between the topsheet and the backsheet. An apertured web can be made to form a fluid pervious topsheet and/or the fluid impervious breathable backsheet.
US 2006/0087053A1 discloses a method for making apertures in a precursor web by moving the web material through a nip of two counter-rotating rollers, wherein a first roller comprises a circumferentially-extending ridges and grooves, and a second roller comprises teeth which are tapered from a base and a tip, and the teeth are joined to the second roller at the base. The base of the tooth has a cross-sectional length dimension greater than a cross-sectional width dimension.
Even with formation of macro apertures for fluid transportation in a micro-textured web, there still is a challenge in fluid drainage as there are flat areas in the web. Especially when microtextures are in the form of discrete extended elements like protrusions, fluid is trapped in valleys among the discrete extended elements. In addition, discrete extended elements are rather fragile, once micro-texturing is completed, it is difficult to create apertures by mechanical deformation such as hot roll as the heat from the hot roll may melt parts of the discrete extended elements and impart permanent deformation into the discrete extended elements, or harden parts of the discrete extended elements which results in plastic and abrasive feels. For example, the heat can cause end edges of discrete extended elements crisp to become very stiff as a result of the exposure to the heat. The crisp or stiffened edges make final products using the web such as absorbent articles rough to the skin.
Therefore, a need exists for apparatuses and methods that capable of mechanically forming macroscopic apertures in a micro-textured web providing an improved fluid handling. A further need exists for apparatuses and methods that capable of mechanically forming macroscopic apertures in a micro-textured web without compromising, even with enhancing desirable softness.